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QSPI

Jim16302
Prodigy 90 points

I am looking for some DSPs which support QSPI (so CPU can reduce the overhead due to interrupt), 320VC5505 is quite suitable for our application because it has a FFT accelator, but 320VC5505 does not support QSPI. Can some one recommend some DSP similar to 5505 but with QSPI (or other interface with similar functionality)?

 

Thanks,

Jim

  • 0
    TI__Guru*** 125430 points

    I had never heard of QSPI so I did a quick search.  From what I could quickly gather it appears to still be standard SPI interface out at the pin level but offers some more capability internally in terms of how it handles the data.  What is it that you will be connecting to?  I didn't see much difference between "QSPI" and simply using DMA+SPI.  Can you help me understand the distinction?  If DMA+SPI is sufficient then 5505 will be a great device for you. 

    EDIT: Apparently DMA cannot be used with SPI on this device.

  • 0 in reply to Brad Griffis
    TI__Expert 3353 points

    One thing I'd like to note is that C5505/05 does not support DMA on the SPI i/f. It supports the DMA from I2S serial i/f.

    Older C5000 devices supported DMA on McBSP i/f which could work as I2S or SPI i/f.

    We'll make it clear in our datasheet about this limitation.

    Thanks,

    - Srik

  • 0 in reply to Srik Gurrapu
    TI__Guru*** 125430 points

    Thanks, Srik.

    Jim, sorry for the confusion.  Could you provide more details on what you're interfacing to and what your application is?  Perhaps someone can recommend another device that will be suitable.

  • 0 in reply to Brad Griffis
    Prodigy 90 points

    Thanks, Brad and Srik,

    I am trying to find some serial ports of C5505 to interface with dual DACs and dual ADCs,  DACs and ADCs are time sharing. The data continuously and periodically comes in and out the C5505, so we need the serial interface which can support DMA functionality. It seems C5505 only support DMA forI2S serial i/f, right?

     

    Thanks,

    Jim

  • 0 in reply to Jim16302
    TI__Guru*** 125430 points

    Yes, 5505 supports DMA on the I2S interface as mentioned in Chapter 2.11 "DMA Event Support" of the 5505 I2S Guide.  What are your A/D requirements?  Can you not find one with an I2S interface?  Since your data is continuous/periodic it seems like I2S would lend itself naturally to that kind of data transfer.

  • 0
    Genius 4630 points

    What about the 320VC5506 or the 5509A? Those support DMA with all 3 McBSP ports.  In fact, I'm using DMA from two ADS chips in parallel at 1 MHz sampling rate each.

    As for FFT acceleration, what do you need?  My application is running a 128-point FFT at a rate of 15,625 FFTs per second, and I'm only using 25% of the available CPU on a 108 MHz C5506.  You may find that the specific FFT acceleration of the C5505 is not needed in your case.  TI has benchmarks for each DSP, and you can calculate the time needed by factoring in the maximum clock rate and the number of cycles.